1,721,002 research outputs found
Persistent Gut Barrier Dysfunction and Mucosal Inflammation after Eradication of Giardia lamblia Infection: Implications for the Pathogenesis of Post-Infectious Irritable Bowel Syndrome
No full text本研究完成了混合式薄膜蒸餾系統之完整設計的最適化設計，並探討了利用內部式回收改良設計的可能性，而研究結果發現內部式回收應用在滲透蒸發單元只改善了部分的設計案例，所以我們利用經過無因次化的方程式來決定究竟回收是否有益。經推導完成的通用架構，進一步了解內部式回收的作用。在此以通用架構探討兩個真實系統：乙醇─水以及異丙醇─水的分離。不含內部式回收的最適化結果證明了不同的共沸組成造成不同的最適化程序組態。乙醇系統的最適化設計包含了單根蒸餾塔加上後接的薄膜單元串接。而異丙醇系統的組態則是需加上第二根蒸餾塔才是較經濟的設計。最後經由分析得知適當應用內部式回收可以進一步改良上述兩個製程。在系統動態方面，兩個製程的控制架構均已建立，並確定了兩個系統的可控制性。而系統動態模擬發現了包含內部式回收的系統動態響應比不含內部式回收的系統較慢。The optimization of complete designs for hybrid membrane-distillation systems is done in this research. The possibility of design improvement by using internal recycle is investigated. Internal recycle in pervaporation only improves the design in some cases. These conditions where internal recycle is beneficial are determined by studying the generalized dimensionless equations. The result is a general framework for understanding internal recycle. Two real systems which are ethanol – water and isopropanol - water system are also investigated. Optimization results without the recycle show the difference in the azeotrope composition causes a difference in the optimum process configuration. The optimal design for ethanol system has a single distillation column followed by a membrane cascade. On other hand, for the isopropyl alcohol system a second distillation column in the configuration gives a better design. The appropriate application of internal recycle further improves the design in both cases. Control structures for these designs are developed to ensure the controllability of the process. The dynamic simulation of the system with internal recycle shows a slower response compared to those without internal recycle
Study of the Machining Characteristics of Polycrystalline Diamond by Wire-EDM
No full text多晶鑽石(Polycrystalline diamond，簡稱PCD)為近年來工業界廣泛使用之材料，其優點除了擁有近似單晶鑽石之優良機械性質外，還能配合目的被加工為所需之形狀。多晶鑽石最常被用於切削加工，而其中一項最新應用是使用於晶圓拋光墊(pad)之鑽石修整器(diamond conditioner)，其為使用放電加工方式將多晶鑽石切割出如金字塔形狀之陣列，稱為ADD TM(Advanced Diamond Disk)。但PCD 因其高硬度及高耐磨性，不適於使用傳統加工，因此本研究使用不受加工材料硬度及韌性等限制之線切割放電加工方式對多晶鑽石進行切割。於多晶鑽石為一多種材料之複合體，其材料性質與一般金屬材料不同，因此本研究分別就三大部分進行實驗與觀察，藉以了解多晶鑽石進行線切割放電加工之特性，以作為日後加工之參考，研究結果發現：(一)改變各個參數對其進行線切割放電加工，可發現PCD 與一般金屬之加工趨勢相近，但放電加工效率較低，其適用之參數範圍也較窄。加工後PCD 上表面之缺陷會因on time 增加而增加，因加工液流量加大及多晶鑽石朝下擺放而減少，此外PCD 放電過後也會導致PCDWC 間的間隙加大。(二)使用鉬線極與鎢線極對多晶鑽石進行加，其速度因線極導電度不佳與殘留之潤滑劑而較低，加工後之PCD 表面狀況也不佳。(三)元素六(Element Six)公司新發展出一種多晶鑽，擁有小晶粒好放電加工但卻耐磨之特性，其放電參數對加工效率之趨勢，大致與一般多晶鑽石相同，且加工後之PCD上表面品質相當好，PCD 與WC 間之間隙也較小。PCD (polycrystalline diamond) is an intergrown mass of randomly orientated diamond particles in a metal matrix. PCD is usually used as cutting tool due to its extremely high hardness and abrasion resistance. One of its new applications is the diamond conditioner for polishing pad in CMP process. The PCD array of pyramid shapes called ADD TM by traditional machining processes is not an easy task due to its extremely high hardness and abrasion resistance. EDM process is considered one of the potential candidates to machine PCD because of the conductive element of Cobalt (Co) contained in PCD. In this paper, wire EDM process is chosen and its machining characteristics are discussed.he material properties of PCD are different from the general metallic materials owing to its multi-materials compound. In order to understand the machining characteristics of PCD by wire-EDM three parts of experiment are conducted. (1) By changing the parameters during the wire-EDM process, the tendency of machiningfficiency in cutting PCD is found to be similar to that of cutting general metallic materials. But its value is lower and the suitable parameters are fewer. The defects on the upper surface of PCD increase under a larger ignition on time condition, and decrease with PCD side placing downward and under a higher water flow rate condition. In addition, after the wire-EDM process, the gap between PCD and WC becomes noticeable. (2) Using Molybdenum (Mo) wire and Tungsten (W) wire as the electrodes of wire-EDM to cut PCD, the efficiency is low because of the inferior electric conductivity and the inherent lubricant on the electrodes. The quality on the upper surface of PCD is poor after wire-EDM machining. (3) Using brass wire as the electrode, cutting a new kind of PCD which not only has a good EDM ability but also a good abrasion resistance developed by Element Six with wire-EDM process is studied. The tendency of machining efficiency approximates to that of cutting other kinds of PCD. But the quality on its upper surface is satisfactorily good and the gap between PCD and WC is also smaller.中文摘要 i文摘要 ii錄 iv目錄 vii目錄 xi號說明 xii一章 緒論 1.1 引言 1.2 文獻回顧 4.3 研究目的與方法 7.4 本文結構 8二章 放電加工原理介紹 9.1 放電加工原理 9.1.1 材料去除機制 9.1.2 放電現象之基本轉換過程 11.1.3 放電火花之結構 13.2 放電電源 15.2.1 依放電迴路分類 15.2.2 依放電控制形式分類 16.3 放電加工之放電迴路 18.4 放電加工參數 20.5 線切割放電加工之特性 22.6 放電波形分類 25三章 實驗設備與實驗規劃 27.1 實驗設備 27.2 線切割放電波形即時監測系統 31.3 實驗規劃 36四章 線切割放電加工多晶鑽石實驗 37.1線切割多晶鑽石特性實驗 37.1.1放電加工參數實驗 37.1.2放電加工多晶鑽石之特性 43.2不同線極線放電加工多晶鑽石實驗 47.2.1放電加工參數實驗 47.2.2鉬、鎢線極放電加工多晶鑽石之特性 52.2.3鉬、鎢線極之斷線機制 55.2.4各線極最適宜之參數設定 59.2.5小結 61.3新型多晶鑽石之放電加工實驗 63.3.1放電加工參數實驗 63.3.2放電加工新型多晶鑽石之特性 66.3.3最適宜之參數設定 69五章 結論與未來展望 71.1結論 71.2未來展望 72考文獻 7
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Effects of somatosensory stimulation and attention on human somatosensory cortex: An fMRI study
No full textIt is well known that primary and non-primary areas of human somatosensory cortex are involved in the processing of adequate deviant/rare stimuli and omission of frequent stimuli. However, the relative weight and interaction of these variables is poorly known. This functional magnetic resonance imaging (fMRI) study tested the hypothesis that somatosensory stimulus processing and attention especially interact in nonprimary somatosensory areas including secondary somatosensory cortex (SII) and insula. To test this hypothesis, responses of somatosensory cortex were mapped during four conditions of an oddball paradigm: DELIVERED COUNT and IGNORE (count or ignore deviant/rare electrical stimuli, respectively); OMITTED COUNT and IGNORE (count or ignore the rare omission of frequent electrical stimuli, respectively). The deviant/rare and frequent electrical stimuli were delivered to median and ulnar nerve, respectively. It was observed that contralateral (left) primary somatosensory responses were not markedly modulated by the mentioned deviant/rare events. Furthermore, contralateral SII and insula responded to all but not OMITTED IGNORE (purely attentive) condition, whereas ipsilateral (right) SII responded to all conditions. Finally, ipsilateral insula responded to the COUNT (attentive) conditions, regardless of the physical presence of the deviant/rare stimuli. The results suggest that in somatosensory modality, bilateral SII and left (contralateral) insula reflect complex integrative processes of stimulus elaboration and attention, whereas right (ipsilateral) insula mainly sub-serves active attention to deviance within a sequence of somatosensory stimuli
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